Method for rearranging the structures of crude oil or crude oil fractions

ABSTRACT

A process for producing useful intermediate products from crude oil or crude oil fractions comprising pyrolysis by contacting the crude oil with high temperature steam to produce a mixture of volatile hydrocarbons and polycyclic aromatic tars and subsequently reacting the tars with hydrogen or an olefin is disclosed.

Unite States atent [191 METHOD FOR REARRANGING THE STRUCTURES OF CRUDE OIL OR CRUDE 01L FRACTIONS Inventors: Takuji Hosol, Tokyo; Koichi Washimi, Fukushima; Masaaki Takahashi, Tokyo; Ryoichi Takahashi; Shinpei Gomi, both of Tokyo, all of Japan I Kureha Kagaku Kogyo Kabushiki Kaisha, Tokyo, Japan Filed: Apr. 23, 1970 Appl. No.: 31,419

Assignee:

Foreign Application Priority Data Apr. 25, 1969 Japan...' 44/31494 U.S-. Cl 208/67, 208/44, 208/144 Int. Cl Cl0g 37/06 Field of Search 208/67, 40, 44, 130,

[451 Aug. 28, 1973 [5 6] References Cited UNITED STATES PATENTS 3,600,298 8/1971 'Mayumi et al 208/44 2,345,877 4/1944 Kroenig 208/4'4 2,662,051 12/1953 Pelzer 208/44 2,752,290 6/1956 Beattie 208/40 2,847,366 8/1958 Boisture..... 208/40 2,970,099 1/1961 lllman 208/40 3,050,457 8/1962 Wilson 208/67 3,324,029 6/1967 King et a1. 208/44 Primary Examiner-Herbert Levine Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak 5 7] ABSTRACT A process for producing useful intermediate products from crude oil or crude oil fractions comprising pyrolysis by contacting the 'crude oil with high temperature steam to produce a mixture of volatile hydrocarbons and polycyclic aromatic tars and subsequently reacting the tars with hydrogen or an olefin is disclosed.

10 Claims, No Drawings METHOD' FOR REARRANGING THE STRUCTURES OF CRUDE OIL OR CRUDE OIL FRACTIONS BACKGROUND OF THE INVENTION ance for supplying naphtha as the raw material, result.

An object of this invention is to provide a method for producing useful petrochemical intermediates by rearranging the structures of crude oil or fractions of crude oil.

I .fnEsoaIPTIoN OF THE INVENTION According to the present invention, crude oil or crude'oil fractions are pyrolized in a first step by steam heated to a high temperature, whereby the raw material is converted into acetylene, ethylene, propylene, hydrogen, benzene, naphthalene, and a heavy tar. The heavy tar thus produced is reacted with hydrogen and- /or olefins in the second step, whereby the heavy tar is converted into a hydrogenated tar and/or an alkylatedtar.

Thus, by the process of the present invention, in addition to the production of useful petrochemical intermediate ipr osiu 'clts, such as acetylene, ethylene, propylene, benzene, and naphthalene, useful hydrogenated and/or 'alkylated tars can be obtained as petrochemical products using heavy tar, which has never hitherto been utilized as raw materials in petrochemical industry.

ln othe'r words, the feature of the present invention is'tha't crude oils as well as all fractions of crude oils can be iis'ed in the process of this invention while conventional systems employed in petrochemical industry for preparing petrochemical intermediate products have used naphtha'from the petroleum refining industry. Accordingly, other petrochemical industry systems can be established independently by the present invention eliminating the-necessity of relying upon the petroleum refining industry, which is considered to be a fuel supplying industry.

DETAILED DESCRIPTION on THE INvENTIoN Now, the method of this invention will be explained in detail. I

In the processot this invention, crude oil or crude oil fractions are injected into high temperature steam heated to a temperature of from l,500 to 2,300C in a first-step reactor and the raw material is pyrolyzed at reaction temperature of from 900 to 1,500C, preferably. from 1,000 to l,300C, for a reaction time of from 0.001 to 0.1 seconds, preferably from 0.002 to 0.01 seconds, and under apressure of from 0.2 to kg/sq. cm., whereby from 30 to 50 percent by weight of acetylene, ethylene and propylene, from 3 to 5 percent by 2 a weight hydrogen, from 5 to 15 percent by weight light aromatics, such as benzene, naphthalene andjthe like,

and from 10 to percentby weight heavy tar comprising polycyclic aromatics are produced.- Of these products, acetylene, ethylene, propylene, benzene, naphthalene, and the like can be utilized as useful intermediates for petrochemical industry. However, heavyta'r is not used as it is as a ,useful intermediate product. Therefore, in the second step of the process, the heavy tar is reacted with thehydrogen and/or olefins presentin the gaseous products at comparatively low temperatures of from 150 to 450C in the presence of a catalyst to provide a hydrogenated tar and/or an alkylated tar. Furthermore, if necessary, the alkylated tar further can be subjected to hydrogenation and appropriate fractional distillation to provide useful products such as insulating oils, special fuels, heat transfer media, plasticizers, paint vehicles, rubber oils, and the like.

The rearrangement of the heavy tar in the second step of this invention is conducted to improve the electrical, thermal and mechanical properties thereof, providing useful products. The hydrogenation of the heavy tar in the second. step usually is conducted under a pressure of from 40 to 200 kg/sq. cm. in thepresence of a catalyst such as cobalt, molybdenum, nickel, tungsten, platinum, and thelike. The alkylation of the heavy tar usually is conducted under a pressure of from 1 to 100 kg/sq.cm. in the presence of a catalyst such as'silica, alumina, zeolite, and the like.

The hydrogen used .in the above-described hydrogenation of heavy tar is present in the gases formed by the pyrolysis in the first step of this invention. The hydrogen in the gases can be separated or not separated from the other components before it is supplied for hydroge nation. Furthermore, in the alkylation of heavy tar, ethylene or propylene separated from the product gases in the first step can be used. Ethylene or propylene contained in the gases produced in the first step can, be used as is. Conversely, the heavy tar produced in the first step can be used as it is in the hydrogenation or alkylation thereof. If desired, it can be subjected further to a fractional distillation before being subjected to hydrogenation or alkylation. The selection of the approach depends on the properties of final products. If desired, the heavy tar produced in the first step can be subjected to desulfurization by the hydrogen treating process before the tar is treated in the second step.

As described above, in the present invention the products formed in the system can be used as the raw EXAMPLE 1 After preheating to 300C, kg/hour of a naphthenic crude oil (Seria crude oil) was injected into steam, heated at 2,000C, by means of a spray nozzle and then subjected to pyrolysis under the conditionsof 3.5 kg/sq.cm. in pressure, l,l00C as the final reaction.

temperature, and 0.003 second in reaction time. The reactor employed was made of heat resistant stainless steel lined with zirconia fire brick. The reaction time was controlled by a quenching method in which low temperature steam was blown into the reactor from the lower section of the reactor to reduce the temperature rapidly in the reactor and prevent overdecomposition and deposition of carbon on the walls of the reactor.

. The products were then introduced into a cooling column, where they were separated into gaseous products and liquid products. The gaseous products were compressed and the carbon dioxide in the gaseous product was separated using an aqueous potassium carbonate solution, the acetylene using a solvent such as acetone or dimethyl formamide and then the ethylene, methane, and hydrogen using a cooling system. With this procedure, 22.0 kg/hour of acetylene, 22.0 kg/hour of ethylene, 2.0 kg/hour of carbon dioxide, 1.3 kg/hour of carbon monoxide, 17.0 kg/hour of methane, and 3.9 kg/hour of hydrogen were obtained.

Then, by subjecting the liquid products to a fractional distillation, 10.9 kg/hour of benzene and naphthalene fractions and 23.1 kg/hour of tar fraction (average molecular weight 200) were recovered.

Thereafter, the residues were removed from the tar fractions and the tar fractions were desulfurized by hydrogen treating, under the conditions of 40 kg/sq.cm. in pressure, 400C in temperature and 0.5 second in reaction period using hydrogen obtained in the pyrolysis in an amount of 5 moles of hydrogen per 1 mole of the fractions, in'a fixed bed-type reactor, in which the olefins and the sulfur contained in the tar were removed. In this hydro-treating, an active alumina, carrying cobalt and molybdenum thereon, was used as the catalyst.

The tar fractions thus hydrotreating were subjected to alkylation with. ethylene, obtained in the pyrolyis, under the conditions of 300C in reaction temperature, a mole ratio of 5 to -1 of ethylene to tar, 30 kg/sq.cm. in pressure, and 0.3 second in reaction time in the presence of an alumina catalyst.

The alkylated tar thus obtained was distilled into a fraction of 280 to 380C and a fraction of 380 to 500C in boiling point adjusted to normal pressure. The former showed quite excellent properties as a heatresistant heat medium or electrical insulating oil. The latter had properties useful as a rubber oil or a plasticizer as well as a vehicle for a thermo-setting resin.

Also, the alkylated tar obtained above was hydrogenated with hydrogen, formed in the pyrolysis, under the conditions of 250C. at reaction temperature, 100 kg/sq.cm. in pressure, a mole ratio of to l of hydrogen to alkylated tar, and 0.8 second in reaction time by passing them through a cylindrical reactor packed with EXAMPLE 2 V a v A paraffinic crude oil (Arabian Lightcrudeoil) was pyrolyzed using the same reactor as described in Exam-3 the same conditions as us'ed. in-Exampleple 1 and under 1.

The product was separated into gaseous products and liquid products using the same procedure as used in Example I. Then, from the gaseous products, carbon dioxide, acetylene and ethylene were separated and the remaining gaseous mixture of hydrogen, methane, and carbon monoxide was used as is in the subsequent reaction as the hydrogen source. The yields for the products were 20.4 percent by weight acetylene, 20.8percent by weight ethylene, 2.0 percent by weight carbon dioxide, 21.2 percent by weight of a gas mixture containing mole percent hydrogen, 10.8 percent by weight benzene-naphthalene fraction, and 23.8 percent by weight of a tar fraction, based on the weight of the crude oil.

Thereafter, the tar fraction was treated with a gas mixture containing hydrogen, obtained in the pyrolysis, in a desulfurization column packed with a cobaltmolybdenum-alumina catalyst under the conditions of 50 kg/sq.cm. in pressure, 400C in temperature, molar ratio 5 to I of hydrogen to tar, and 0.5 second in reac tion time, whereby olefins and sulfur were removed. Then, the tar fraction thus treated was hydrogenated in a hydrogenation column packed with a nickel-alumina catalyst using the above-described hydrogencontaining gas mixture, obtained in the pyrolysis, under the conditions of 250C in reaction temperature, kg/sq.cm. in pressure, mole ratio of 10 to 1 of hydrogen to tar, and 0.8 second in reaction time. The hydrogenated tar was then distilled into a fraction of 200300C and a fraction of higher than 300C.

The former had excellent properties as a fuel or a'solvent, while the latter had excellent properties as a plasticizer or a softening agent for plastics and rubbers.

EXAMPLE 3 A paraffinic crude oil (Arabian Light crude oil) was pyrolyzed using the same reactor and under the same condition as described in Example 1 except the reaction temperature was 900C and reaction time was 0.01 second.

The product was separated into gaseous products and liquid products using the same procedure as used in Example 1. Further from the gaseous products, carbon dioxide, acetylene, ethylene and propylene were sepa rated and the remaining gas mixture of hydrogen, methane, and carbon monoxide was used as is in the subsequent reaction as the hydrogen source. The product yield was 10.8 percent by weight of acetylene, 24.8 percent by weight ethylene, 14.1 percent by weight propylene, 1.3 percent by weight carbon dioxide, 18.0 percent by weight of a gas mixture containing 50 mol percent hydrogen, 9.5 percent benzene-naphthalene fraction, 11.5 percent by weight tar fraction based on the weight of the crude oil.

The tar fraction was treated with the gas mixture containing hydrogen obtained in the pyrolysis in the desulfurization column packed with a cobalt-nickel-alumina catalyst under the conditions of 50 kglsq.cm. in pressure, 400C in temperature, mole ratio of 5 to l of hydrogen to tar, and 0.5 second in reaction time, whereby the olefins and sulfur were removed. Then this tar fraction was alkylated in an alkylation apparatus packed with a silica-alumina catalyst using the propylene obtained in the pyrolysis under the conditions of 300C in reaction temperature, 50 kg/sq.cm in pressure, mole ratio of 5 to 1 of propylene to tar, and 0.3 second in reaction time. The propylated tar was then distilled into a fraction of 200 to 300C and a fraction of higher than 300C.

The former has good properties as a heat transfer oil or a solvent, while the latter has excellent properties as a softening agent for rubber.

What is claimed is:

l. A method of rearranging the structure of petroleum hydrocarbons contained in crude oil to produce useful intermediate products comprising:

1. pyrolyzing a crude oil or a heavy fraction thereof with steam at a high temperature to produce a gaseous mixture comprising hydrogen, hydrocarbons and polycyclic aromatic tars;

2. desufurizing said polycyclic aromatic tars by hydrogenating said polycyclic aromatic tars with the hydrogen produced in step (I); and

3. hydrogenating the product of step (2) with the hydrogen produced in step (1) at a temperature of from 150 to 450C. and at a pressure of from 40 to 200 kg/cm.

2. The method as claimed in claim 1, wherein said steam used in step (1) is at a temperature of from l,500 to 2,300C.

3. The method as claimed in claim 1, wherein the pyrolysis in step (1) is conducted at a reaction temperadrogen, 5 to 15 percent light aromatics and 10 to 30 of polycyclic aromatic tars. I

6. The method of claim 1 wherein said desulfurizing step is conducted in the presence of a desulfurizing catalyst.

7. The method of claim 1 wherein said hydrogenating step is conducted in the presence of a hydrogenation catalyst. I

8. The method of claim 1 wherein the product of step (2), before being hydrogenated in step (3), is subjected to a fractional distillation.

9. The method of claim 5 wherein the product of step (1), before being desulfurizedin step 2), is subjected to a fractional distillation.

10. The method of claim 1 consisting of the recited steps. 

2. The method as claimed in claim 1, wherein said steam used in step (1) is at a temperature of from 1,500* to 2,300*C.
 2. desufurizing said polycyclic aromatic tars by hydrogenating said polycyclic aromatic tars with the hydrogen produced in step (1); and
 3. hydrogenating the product of step (2) with the hydrogen produced in step (1) at a temperature of from 150* to 450*C. and at a pressure of from 40 to 200 kg/cm2.
 3. The method as claimed in claim 1, wherein the pyrolysis in step (1) is conducted at a reaction temperature of from 900* to 1,500*C for a period of from 0.001 to 0.1 second.
 4. The method as claimed in claim 1, wherein the pyrolysis is conducted by spraying the crude oil raw material into the steam.
 5. The method of claim 1 wherein said gaseous mixture produced in step (1) comprises 30 to 50 percent acetylene, ethylene and propylene, 3 to 5 percent hydrogen, 5 to 15 percent light aromatics and 10 to 30 of polycyclic aromatic tars.
 6. The method of claim 1 wherein said desulfurizing step is conducted in the presence of a desulfurizing catalyst.
 7. The method of claim 1 wherein said hydrogenating step is conducted in the presence of a hydrogenation catalyst.
 8. The method of claim 1 wherein the product of step (2), before being hydrogenated in step (3), is subjected to a fractional distillation.
 9. The method of claim 5 wherein the product of step (1), before being desulfurized in step (2), is subjected to a fractional distillation.
 10. The method of claim 1 consisting of the recited steps. 